HBK Measurement System Helps To Get Viking Ships on the Move

Meeting the Need

To move the ships safely and securely, a steel rig will be built around them and a temporary rail system will be laid down. From here, the ships will be lowered down to the new exhibition area. However, before the steel ring can be created, engineers need to collate adequate data. Moving and weighing ships can often be a challenging task as changes in loads or stresses must be minimised or preferably eliminated. To address this, engineers on this project identified many lifting/weighing points and ensured that these points were placed in locations already bearing load. 

In practice, this meant fastening load cells on all vertical supports, and carefully selecting where to place them on the keel support beam, which is the large, shaped beam upon where the ships’ keel rests. Furthermore, to avoid any new stresses, all load cells were placed in pairs.

On the vertical supports, a split bar was clamped to transfer force to the load cells via threaded rods. Angular brackets were also screwed to the side of the keel beam with two 12mm threaded rods connecting the two brackets. Vertical threaded rods again transferred the load to the load cells. When everything was in place, engineers slowly lifted the ship 2.5mm by carefully turning the nuts on these rods in a pre-planned sequence. This was enough to establish weight.

However, when the time came to weigh the bigger Gokstad ship, there were some additional challenges, and this is where HBK was able to help. As weighing points along the keel support beam were being utilised in the moving rig, instead of fastening the brackets that transfer force to the load cells with screws and two approximately placed 12mm rods, engineers needed to use three 24mm hardened steel rods at the lifting point. As these had to be placed with high precision, large holes had to be carefully drilled, whilst causing minimum vibration to the ship.

For this project, Z6 load cells from HBK were installed on various measuring points and connected to a QuantumX MX1615B Strain Gauge Amplifier with catman® AP software.

“For such a prestigious project, it was important that we choose the right equipment for the job and that’s why we turned to HBK”,

explains Anders Helseth Nilsson, Department of Collection Management, Museum of Cultural History.

“In addition to delivering an exceptional product that met the demands of the task, HBK also delivered the customer service to match, both in terms of the design and quickly solving any issues we had along the way”.

The MX1615B is part of the QuantumX family that offers compact strain gauge amplifiers that deliver accurate results for both dynamic and static measurements. Suitable for precise and safe data acquisition of strain gauges in full-bridge, half-bridge, and quarter-bridge configuration, as well as strain gauge-based transducers, potentiometers, resistance thermometers (PT100) or normalised voltage (+/-10V), the MX1615B is ideal choice whenever strains, forces and displacements are acquired. Equipped with 16 sensor inputs and arranged in compact housing, typical application areas include static stress tests for FEM models, quasi-dynamic fatigue tests for life analysis, monitoring tasks, material investigations, residual stress analysis, maintenance tasks, as well as for general recording of the load data in the field.  Used with catman® AP software, simple data analysis can be achieved.

Following previous experience with another system whereby hardware had performed considerably better than software, the QuantumX with catman® AP software provided the museum with a complete system which is enabling it to continue to achieve accurate and reliable results.